1. Area of the Art
The present application is in the art of landscaping and is directed to a product and method for making recent construction, including rock cuts and concrete, blend into the surrounding terrain.
2. Description of the Background Art
New construction particularly when exposed rock and soil surfaces are altered often fails to harmonize with the surrounding terrain because altered surfaces are colored differently than the native surfaces. When the construction contains concrete and metal (iron and steel) components, the new concrete and metal may also present a harsh appearance in spite of the use of concrete coloring agents and metal covering paints. These problems are exacerbated in relatively arid regions like the Southwestern portion of the United States both because the aridity slows the growth of natural vegetation that will in time cover the altered surfaces, and because in relatively arid regions rock surfaces are naturally covered with “desert varnish” a coating that is often much different in color than the “naked” rock surface. The presence of the “desert varnish” makes any alteration to the rock surface that much more obvious.
Because natural coloration to rock surfaces such as “desert varnish” develops slowly over a period of years or even decades or longer, there have been efforts to apply materials to more rapidly mask alteration to the surface so that new construction can more rapidly blend in. The most commonly used approach has been to apply coloring liquids not unlike paints or stains used on wood. Commercially available formulations of paint-like materials available for coloring rock surfaces tend to be superficial and, thus, are readily weathered, commonly fading within as little as a few months. Such liquids gain most of their tinting or coloring power from blending a dye or pigment into a liquid carrier or vehicle such as latex, oil or organic solvent. With even minimal weathering from ambient sunlight, wind or rain such a superficial coating may readily slough from the treated surface and/or the pigments may fade or change hue. Further, because the coloring agent's primary means of attachment to the rock or other surface relies almost entirely upon surface adhesion, the bond between the color and the surface is at best weak and lacks the permanence that is desired.
There have been attempts to more closely replicate naturally developed surface coloration. U.S. Pat. Nos. 4,725,451 and 4,812,340 to Cripe describe a method of simulating “desert varnish” by first reacting the rock surface with a liquid alkali base and then applying a coloring layer of a metallic salts such as iron or manganese salts. U.S. Pat. No. 5,308,646 to Moore discloses a method of applying metal acetate salts to rock surfaces to mimic “desert varnish.” This reference particularly prefers the application of iron acetate and manganese acetate. Iron salts are known to impart reddish “rust” colors when they become oxidized. Manganese oxide is black/purple and is believed to be a principle coloring agent in natural “desert varnish.” Recent research has confirmed the presence of manganese in “desert varnish” but has also surprisingly revealed that a major constituent of natural “desert varnish” is clay powder apparently from a wind blown source. It is also known that lithophilic bacteria inhabit the surface layers of rocks are at least partially responsible for the process that binds the clay particles and oxidizes the manganese ions to form natural “desert varnish.”